local function fd(x, y, ang, steps, penDown)
   local x2, y2 = x+math.sin(ang)*steps, y-math.cos(ang)*steps
   if penDown then
      love.graphics.line(x, y, x2, y2)
   end
   return x2, y2
end

local deg2rad = math.pi/180
function mkTurtle(x,y,degrees,orig)
   local penDown = true
   if x == nil then x = 0 end
   if y == nil then y = 0 end
   if degrees == nil then degrees = 0 end

   local self
   self = {
      fd = function(steps)
	 x, y = fd(x, y, degrees*deg2rad, steps, penDown)
	 return self
      end,

      bk = function(steps)
	 x, y = fd(x, y, degrees*deg2rad, -steps, penDown)
	 return self
      end,

      rt = function(deg)
	 degrees = degrees + deg
	 return self
      end,

      lt = function(deg)
	 degrees = degrees - deg
	 return self
      end,

      pd = function(isDown)
	 penDown = isDown
	 return self
      end,

      col = function(color)
	 -- FIXME
	 return self
      end,

      dup = function(orig)
	 return mkTurtle(x, y, degrees, orig)
      end,

      parent = function()
	 return orig
      end,

      inline = function(env, func)
	 local stub = {}
	 local meta = {
	    __index = function(table, key)
	       if env[key] ~= nil then
		  return env[key]
	       end
	       if _ENV ~= nil and _ENV[key] ~= nil then
		  return _ENV[key]
	       end
	       return nil
	    end,
	 }
	 setmetatable(stub, meta)
	 setfenv(func, stub)
	 return func()
      end,
   }
   return self
end

return mkTurtle